Storage system and remote copy control method for storage system

Abstract

A storage system of this invention maintains consistency of the stored contents between volumes even when a plurality of remote copying operations are executed asynchronously. A plurality of primary storage control devices and a plurality of secondary storage control devices are connected by a plurality of paths, and remote copying is performed asynchronously between respective first volumes and second volumes. Write data transferred from the primary storage control device to the secondary storage control device is held in a write data storage portion. Update order information, including write times and sequential numbers, is managed by update order information management portions. An update control portion collects update order information from each update order information management portion, determines the time at which update of each second volume is possible, and notifies each-update portion. By this means, the stored contents of each second volume can be updated up to the time at which update is possible.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application relates to and claims priority from Japanese Patent Application No. 2006-87983, filed on Mar. 28, 2006, the entire disclosure of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to a storage system and to a remote copy control method for a storage system.[0004]2. Description of the Related Art[0005]In the computer systems of recent years, the quantities of data used are increasing, and data is also updated with increasing frequency. Hence methods for backing up such data, or for promptly restoring a normal operating state after occurrence of a fault, are vital issues for storage technology.[0006]As one solution to such problems, technology has been proposed in which, for example, a plurality of storage control devices *are placed in both a primary site and a secondary site, mutually separated, each of the storage control devices at the primary...

AI Technical Summary

Benefits of technology

[0011]This invention was devised in light of the above problems, and has as an object the provision of a storage system and a remote copy control method for a storage system which are able to maintain data consistency when transferring and updating data between a plurality of storage control devices. A further object of this invention is to provide a storage system an...

Problems solved by technology

Hence methods for backing up such data, or for promptly restoring a normal operating state after occurrence of a fault, are vital issues for storage technology.

In the above technology of the prior art, because the primary host and secondary host constantly perform data transfer and reflection processing (processing to write data to a volume in the order of the write time), the load on each host is considerable.

As a result, circumstances arise in which write data which has been received by one secondary storage control device has not yet been received by another secondary storage control device.

Thus when simultaneously executing a plurality of remote copy processing tasks between a primary site and a secondary site, because the states of progress of the various remote copy processing tasks differ, it is difficult to maintain data consistency.

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